The present invention relates generally to exterior rear view mirror assemblies and more specifically to such mirror assemblies of the so called breakaway design.
In recent years, motor vehicle manufacturers have incorporated exterior mirror assemblies in which the mirror is movably supported within a housing and the housing is pivotably supported on an upstanding post forming a part of a supporting base which base is in turn secured to the motor vehicle. Such designs offer significant advantages over prior exterior mirrors in that the housing protects the mirror from being bumped and moved out of adjustment by passerbys and the pivotable mounting allows the housing to fold backwardly or forwardly in the event it encounters an obstacle thus preventing damage to the mirror assembly. Typically, a spring loaded detent assembly is incorporated between the mirror housing and supporting base to retain the mirror in an operative position.
In order to inhibit any vibrational movement of the mirror assembly, it is important that the pivotable connection between the mirror housing (to which the mirror is secured) and the upstanding post of the supporting base be subjected to a predetermined desired claiming force. A typical manner of providing this clamping force has been to provide a semicircular seat on the mirror housing and a separate strap which is then secured to the mirror housing in overlying relationship to the upstanding post. Suitable threaded fasteners are normally used at opposite ends of the strap to secure it to the housing. While this arrangement provides a satisfactory clamping force when new, there is a tendency for the fasteners to loosen over time due to vibration, temperature cycling and the like. Because the fasteners securing the strap to the housing are generally concealed by an outer case and/or the mirror itself, tightening of the fasteners becomes a difficult and time consuming process requiring removal of the outer case and/or mirror itself. Additionally, the prior clamping arrangement is relatively costly in terms of assembling in that it requires separate fabrication, handling and installation of the strap and plurality of fasteners.
The present invention, however, overcomes the disadvantages of the prior clamping arrangement while still providing a strong, reliable, easily adjusted breakaway-type mounting arrangement for the mirror assembly. In the present invention, the fasteners utilized to provide the required clamping force are positioned within the outer case such that they are easily and conveniently accessible by merely tilting the mirror to an extreme inboard position. Once the fasteners have been adjusted, the mirror may be easily tilted back to its normal operative position in which the fasteners are substantially concealed thereby maintaining the aesthetically pleasing clean lines of the mirror assembly. Additionally, the clamping structure of the present invention is integrally formed with the mirror support frame thus eliminating the need to separately fabricate and assemble a strap member. Rather, only a suitable number of fasteners need be assembled to the support frame and tightened to the desired degree to secure the mirror housing to the upstanding post of the bracket frame. Thus, the mirror assembly of the present invention provides a breakaway mounting arrangement which offers the advantage of grater ease of serviceability while also incorporating a more efficient, less costly clamping arrangement while preserving the smooth aesthetically pleasing appearance and durability of the mirror assembly.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.